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/* generate.c -- generates file execgen.c from instruction set
   Copyright (C) 1999 Damjan Lampret, lampret@opencores.org
 
This file is part of OpenRISC 1000 Architectural Simulator.
 
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
 
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
 
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <ctype.h>
 
#include "config.h"
#include "opcode/or32.h"
#include "abstract.h"
#include "labels.h"
#include "parse.h"
#include "execute.h"
 
#define LEAF_FLAG         (0x80000000)
#define SHIFT {int i; for (i = 0; i < level; i++) fprintf (fo, "  ");}
 
extern unsigned long *automata;
extern struct temp_insn_struct {
  unsigned long insn;
  unsigned long insn_mask;
  int in_pass;
} *ti;
 
static char *in_file;
unsigned long op[MAX_OPERANDS];
int num_op;
 
inline void debug(int level, const char *format, ...)
{
  char *p;
  va_list ap;
 
#if DEBUG
  if ((p = malloc(1000)) == NULL)
    return;
  va_start(ap, format);
  (void) vsnprintf(p, 1000, format, ap);
  va_end(ap);
  printf("%s\n", p);
  fflush(stdout);
  free(p);
#endif
}
 
/* Whether this instruction stores something in register */
static int write_to_reg = 0;
 
static int olevel;
 
/* Following functions recursivelly searches for substrings eval_operand and
   set_operand (see functions with the same name in execute.c) and replaces
   them with optimized code. */
char *replace_operands (FILE *fo, char *str) {
  int replace = 0;
  if (*str == '}') {olevel--;}
  else if (*str == '{') {olevel++;}
  else if (strncmp ("eval_operand", str, 12) == 0) {
    replace = 1; str += 12;
  } else if (strncmp ("set_operand", str, 11) == 0) {
    replace = 2; str += 11;
  }
  if (replace) {
    int width, oper;
    sscanf (str, "%i(%i", &width, &oper);
    while (*str && *str != '(') str++;
    while (*str && *str != ',') str++;
    str++;
    if (replace == 1) {
      if (op[oper] & OPTYPE_DIS) {
        fprintf (fo, "eval_mem%i (%c", width, 'a' + oper);
      } else { 
        if (op[oper] & OPTYPE_REG) {
          fprintf (fo, "(reg[%c]", 'a' + oper);
        } else {
          fprintf (fo, "(%c", 'a' + oper);
        }
      }
    } else {
      op[oper] |= OPTYPE_DST;
      if (op[oper] & OPTYPE_DIS) {
        fprintf (fo, "set_mem%i(%c,", width, 'a' + oper);
      } else if (op[oper] & OPTYPE_REG) {
        fprintf (fo, "reg[%c] = (", 'a' + oper);
        write_to_reg = 1;
      } else {
        fprintf (stderr, "Invalid operand type.\n");
        exit (1);
      }
      while (*str != ',') str = replace_operands (fo, str) + 1;
    }
    while (*str && *str != ')') str++;
    if (op[oper] & OPTYPE_DIS) fprintf (fo, ", &breakpoint)");
    else fprintf (fo, ")");
  } else {
    fputc (*str, fo);
  }
  return str;
}
 
/* Generates a execute sequence for one instruction */
int output_function (FILE *fo, const char *func_name, int level)
{
  FILE *fi;
  if ((fi = fopen (in_file, "rt")) == NULL) return 1;
  while (!feof (fi)) {
    char line[10000], *str = line;
    fgets (str, sizeof (line), fi);
    line[sizeof(line) - 1] = 0;
    if (strncmp (str, "INSTRUCTION (", 13) == 0) {
      char *s;
      str += 13;
      while (isspace (*str)) str++;
      s = str;
      while (*s && *s != ')') s++;
      *s = 0;
      while (isspace(*(s - 1))) s--;
      *s = 0;
      if (strcmp (str, func_name) == 0) {
        olevel = 1;
        str += strlen (str) + 1;
        while (isspace (*str)) str++;
        s = str;
        while (*s && *s != '\n' && *s != '\r') s++;
        *s = 0;
        while (isspace(*(s - 1))) s--;
        *s = 0;
        fprintf (fo, "%s", str);
        fprintf (fo, "   /* \"%s\" */\n", func_name);
        SHIFT;
        do {
          fgets (line, sizeof (line), fi);
          line[sizeof(line) - 1] = 0;
          for (str = line; *str; str++) {
            str = replace_operands (fo, str);
          }
          SHIFT;
        } while (olevel);
        return 0;
      }
    }
  }
  fprintf (fo, "{\n");
  level++;
  SHIFT; fprintf (fo, "%s ();\n", func_name);
  level--;
  SHIFT; fprintf (fo, "}");
  return 0;
}
 
/* Parses and puts operands into op[] structure.
   Replacement for eval_operands routine. */
 
static void
gen_eval_operands (FILE *fo, int insn_index, int level)
{
  struct insn_op_struct *opd = op_start[insn_index];
  int dis = 0;
  int no = 0;
  int firstd = 1;
 
  while (1)
    {
      int nbits = 0, first = 1;
      while (1)
        {
          SHIFT; fprintf (fo, "tmp %s= ((insn  >> %i) & 0x%08x) << %i;\n", first ? "" : "|", opd->type & OPTYPE_SHR, (1 << opd->data) - 1, nbits);
          nbits += opd->data;
          if (opd->type & OPTYPE_OP)
            break;
          opd++;
          first = 0;
        }
 
      /* Do we have to sign extend? */
      if (opd->type & OPTYPE_SIG)
        {
          int sbit = (opd->type & OPTYPE_SBIT) >> OPTYPE_SBIT_SHR;
          SHIFT; fprintf (fo, "if (tmp & (1 << %i)) tmp |= 0xFFFFFFFF << %i; /* Sign extend */\n", sbit, sbit);
        }
      if (opd->type & OPTYPE_DIS) {
        /* We have to read register later.  */
        SHIFT; fprintf (fo, "data %s= tmp;\n", firstd ? "" : "+");
        firstd = 0;
        dis = 1;
      } else
        {
          if (dis && (opd->type & OPTYPE_REG)) {
            if (MAX_GPRS == (1 << nbits)) {
              SHIFT; fprintf (fo, "%c = data + reg [tmp];\n", 'a' + no);
            } else {
              SHIFT; fprintf (fo, "%c = data + eval_reg32 (tmp);\n", 'a' + no);
            }
          } else {
            SHIFT; fprintf (fo, "%c = tmp;\n", 'a' + no);
          }
          op[no] = opd->type | (dis ? OPTYPE_DIS : 0);
          no++;
          firstd = 1;
          dis = 0;
        }
      if(opd->type & OPTYPE_LAST) goto last;
      opd++;
    }
 
last:
  num_op = no;
}
 
/* Generates decode and execute for one instruction instance */
int output_call (FILE *fo, int index, int level)
{
  int i;
  printf ("%i:%s\n", index, insn_name (index));
  fprintf (fo, "{\n");
  level++;
  if (index >= 0) {
    SHIFT; fprintf (fo, "unsigned long data, tmp;\n");
    SHIFT; fprintf (fo, "unsigned long a, b, c; /* operands */\n");
  }
  write_to_reg = 0;
  if (index >= 0)
    gen_eval_operands (fo, index, level);
  else
    num_op = 0;
  SHIFT; 
  if (index < 0) output_function (fo, "l_invalid", level);
  else output_function (fo, or32_opcodes[index].function_name, level);
  fprintf (fo, "\n");
 
  SHIFT; fprintf (fo, "if (do_stats) {\n");
  level++;
  SHIFT; fprintf (fo, "num_op = %i;\n", num_op);
  if (num_op) {SHIFT; fprintf (fo, "  op = &current->op[0];\n");}
  SHIFT; fprintf (fo, "current->insn_index = %i;   /* \"%s\" */\n", index, insn_name (index));
  for (i = 0; i < num_op; i++) {
    SHIFT; fprintf (fo, "op[%i] = %c;\n", i, 'a' + i);
    SHIFT; fprintf (fo, "op[%i + MAX_OPERANDS] = 0x%08x;\n", i, op[i]);
  }
  SHIFT; fprintf (fo, "analysis(current);\n");
  level--;
  SHIFT; fprintf (fo, "}\n");
  if (write_to_reg) {
    SHIFT; fprintf (fo, "reg[0] = 0; /* Repair in case we changed it */\n", i);
  }
  level--;
  SHIFT; fprintf (fo, "}");
  return 0;
}
 
/* Generates .c file header */
int generate_header (FILE *fo)
{
  fprintf (fo, "/* This file was automatically generated by generate (see cpu/or32/generate.c) */\n\n");
  fprintf (fo, "static inline void decode_execute (struct iqueue_entry *current)\n{\n");
  fprintf (fo, "  unsigned long insn = current->insn;\n");
  return 0;
}
 
/* Generates .c file footer */
int generate_footer (FILE *fo)
{
  fprintf (fo, "}\n");
  return 0;
}
 
/* Decodes all instructions and generates code for that.  This function
   is similar to insn_decode, except it decodes all instructions. */
static int generate_body (FILE *fo, unsigned long *a, unsigned long cur_mask, int level)
{
  int i;
  if (!(*a & LEAF_FLAG)) {
    unsigned int shift = *a++;
    unsigned int mask  = *a++;
    int prev_invalid = 0;
    fprintf (fo, "\n");
    SHIFT; fprintf (fo, "/* (insn >> %i) & 0x%x */\n", shift, mask);
    SHIFT; fprintf (fo, "switch ((insn >> %i) & 0x%x) {\n", shift, mask);
    level++;
 
    /* Print each case recursively */
    for (i = 0; i <= mask; i++, a++) {
      /* Group invalid instruction decodes together */
      if (!*a) {
        if (prev_invalid) fprintf (fo, "\n");
        prev_invalid = 1;
        SHIFT; fprintf (fo, "case 0x%02x: ", i);
      } else {
        if (prev_invalid) {
          if (output_call (fo, -1, level)) return 1;
          fprintf (fo, "  break;\n");
        }
        SHIFT; fprintf (fo, "case 0x%02x: ", i);
        if (generate_body (fo, automata + *a, cur_mask | (mask << shift), level + 1)) return 1;
        prev_invalid = 0;
      }
    }
    if (prev_invalid) {
      if (output_call (fo, -1, level)) return 1;
      fprintf (fo, "  break;\n");
    }
    level--;
    if (level > 1)
      fprintf (fo, "}  break;\n");
    else 
      fprintf (fo, "}\n");
  } else {
    i = *a & ~LEAF_FLAG;
    /* Final check - do we have direct match?
       (based on or32_opcodes this should be the only possibility,
       but in case of invalid/missing instruction we must perform a check)  */
 
    if (ti[i].insn_mask != cur_mask) {
      fprintf (fo, "\n");
      SHIFT; fprintf (fo, "/* Not unique: real mask %08x and current mask %08x differ - do final check */\n", ti[i].insn_mask, cur_mask);
      SHIFT; fprintf (fo, "if ((insn & 0x%08x) == 0x%08x) ", ti[i].insn_mask, ti[i].insn);
      output_call (fo, i, level);
      fprintf (fo, " else ");
      if (output_call (fo, -1, level)) return 1;
    } else {
      output_call (fo, i, level - 1);
    }
    fprintf (fo, "  break;\n");
  }
  return 0;
}
 
/* Main function; it takes two parameters:
   input_file(possibly insnset.c) output_file(possibly execgen.c)*/
int main (int argc, char *argv[])
{
  FILE *fo;
 
  if (argc != 3) {
    fprintf (stderr, "USAGE: generate input_file(possibly insnset.c) output_file(possibly execgen.c)\n");
    exit (-1);
  }
 
  in_file = argv[1];
  if (!(fo = fopen (argv[2], "wt+"))) {
    fprintf (stderr, "Cannot create '%s'.\n", argv[2]);
    exit (1);
  }
 
  build_automata ();
  if (generate_header (fo)) {fprintf (stderr, "generate_header\n"); return 1;}
  if (generate_body (fo, automata, 0, 1)) {fprintf (stderr, "generate_body\n"); return 1;}
  if (generate_footer (fo)) {fprintf (stderr, "generate_footer\n"); return 1;}
  fclose (fo);
  destruct_automata ();
  return 0;
}